In general, image information possesses object information, which indicates attributes, etc., of the image, as bit information, and the object information is used as important information when this image information is developed and rendered.
When image information is encoded, it is desired that the information be encoded in conformance with the image characteristics specified by attribute information, etc., possessed by this image information. When image information is encoded, therefore, an image region having certain characteristics within the image is designated and an attempt is made to encode this region using a technique that is different from that applied to other regions. In order to designate such a region, however, the designation is made manually or the region is fixed to one that has been predetermined.
Conventionally, in a printing apparatus capable of printing a bitmapped image the basis of an input print instruction, generating attribute information about the bitmapped image by using the print instruction and attribute information of the print instruction, compressing/decompressing the bitmapped image, and outputting the bitmapped image, a single compressing/decompression parameter is set for the overall bitmapped image.
Even if a compression/decompression parameter can be set for a part of a bitmapped image, compression/decompression parameters are only switched in accordance with a target area instruction from a user, but the attribute information of the bitmapped image which is generated by using the print instruction and the attribute information of the print instruction is not used.
Owing to requirements for higher image quality, higher resolution, and the like, no attempt has been made to variably set compression/decompression parameters for a predetermined portion of a bitmapped image or perform efficient compression/decompression parameter control using attribute information.